Even though polycystic ovarian syndrome (PCOS) and/or hperandrogenism, insulin resistance acanthosis nigricans (HAIR/AN) is extensively studied in adult women, the pediatric literature remains deficient. The manifestations of the syndrome in the premenarchal and/or peripubertal female remains poorly described, if at all. Moreover, the pathophysiology of hyperinsulinemia remains uncertain. It is not known if hyperinsulinemia is a compensatory mechanism secondary to insulin resistance, or if it is an early and primary abnormality of pancreatic B-cell hypersecretion. Therefore, the aims of this proposal are: 1) to characterize the metabolic profile of children HAIR-AN/PCOS by investigating the balance between insulin secretion and action. To assess the effects of Metformin treatment in adolescents with PCOS and imparied glucose tolerance on insulin sensitivity and hyperandrogenemia.